system = Module("system");
io = Module("io");
print = system.out.write_line;

path = io.Path(system.script) / "..";
print(path);
if ((path / "path.xm").__string() != system.script) throw Throwable("must equal.");
if ((io.Path(".") / "..").__string() != io.Path("..").__string()) throw Throwable("must equal.");
